In oral arguments in the Supreme Court this week over the constitutionality of President Barack Obama’s health care plan’s requirement that individuals must buy health insurance, Justice Antonin Scalia posed to Obama’s solicitor general a fundamental question that the mandate raises about the nature of the U.S. government.

“If the government can do this, what else can it not do?” asked Scalia.

Scalia asked the question in the context of quizzing Solicitor General Donald Verrilli on the administration’s claim that forcing people to buy health insurance is justified by the clause in Article 1, Section 8 of the Constitution that allows Congress to “make all Laws which shall be necessary and proper for carrying into Execution the foregoing Powers.” In this case, the administration argued that the “foregoing power” that made forcing people to buy health insurance a “necessary and proper” act of Congress was the Commerce Clause.